MPEG portable sound reproducing system and a reproducing method thereof

ABSTRACT

Disclosed is an MPEG portable sound reproducing system and a method for reproducing sound data compressed using the MPEG method. The inventive system includes power supply means for supplying operational power to the system, the power supply means being realized through a secondary battery; power processing means for rectifying power supplied from the power supply means to stable voltage and current; information display means for displaying numbers and combinations of letters related to operational states of the system; control means for controlling all operations of converting and reproducing sound data compressed using the MPEG method; data storage means for storing MPEG-compressed sound data in a designated address according to signals output from the control means; information selecting means for selecting general operations to reproduce, download, and apply selected sound data stored in the data storage means; sound reproducing means for converting sound data stored in the data storage means into a format audible to users according to signals output from the control means; and transmitting/receiving means for transmitting and receiving sound data and program data from external devices.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a portable sound reproducing system andmethod, and more particularly, to a portable sound reproducing systemand a reproducing method thereof in which sound data, compressed usingthe Moving Picture Experts Group (MPEG) method and stored in a memorydevice, is converted into an audible format and output throughheadphones, speakers, etc.

(b) Description of the Related Art

Generally, data processed to be listened or viewed is stored in a memorymedium then output through a reproduction device. The most commonexamples include analog data stored on magnetic tape which is outputthrough a cassette player, and digital data stored on a compact discwhich is output through a compact disc player.

Recent developments in digital technology has enabled memory media usedin personal computers to undergo vast improvements. Namely, memory mediaused in PCs are becoming increasingly lightweight and compact, andproviding the user with more capacity to store memory.

However, with the increase in required memory needed to run operatingsystems and application software, there is a limit to how efficientlymemory media can be used. In an attempt to remedy this problem, avariety of methods have been devised to enable the efficient use ofdigital data. The MPEG standard is one of these methods which increasesthe storage capacity of memory media by compressing data stored therein.

Namely, by using the MPEG method of compressing data, data is compressedto roughly one-twelfth its original size without compromising sound orvisual quality. After compresing data utilizing software or hardwaremade for this purpose, the data is then stored in a storage medium, thenconverted back into its original state using the MPEG method such thatthe data is placed in a form that can be heard or seen by the user. TheMPEG method, therefore greatly increases data storage capacity.

With all the conventional sound reproduction systems, i.e., tape playersand compact disc players, and PCs, etc. which are equipped with thecapability to reproduce MPEG-compressed data, many disadvantages areencountered by the user.

In particular, in using cassette players, which reproduce data stored onmagnetic tape, because the same amount of time is needed to store(record) data as it does to reproduce (play) the data, the storingprocess is time-consuming, and heat generated during the process acts todeteriorate the quality of the recording such that the quality of thesound reproduced is decreased. Moreover, because magnetic tape is easilyworn, the repetitive playing of data stored on the cassette tape alsoacts to reduce sound quality.

Compact disc players and the discs used therein also have many problems.Namely, recording is not possible on compact discs. Further, because ofthe mechanical fragility of CD players, reproduction malfunctions occurwhen the players receive even slight outside shocks. Finally, CD playershave a limited life span as the mechanical parts in the devices oftenbreak over time.

The storage media used in cassette and CD players also have the drawbackof occupying much space. Also, users must take great care that thestorage media are placed in an area that is not exposed to heat, directsunlight, etc.

With regard to prior art devices such as PCs used to reproduce datastored using the MPEG method, as these devices are not portable, thelocation at which users can access the sound and images is limited tothe location of the device. In addition, when using a PC to reproducedata compressed using the MPEG method, the cost of equipping the PC withsoftware or hardware to enable this function is high. Also, becausevarious types of sound data are stored on a plurality of storage media,the user must purchase many kinds of storage media and undergocomplicated processes to reproduce the data stored therein.

Finally, in all of the above cases, users must physically go to retailstores to purchase storage media, causing inconvenience to the user.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to solve the aboveproblems. It is an object of the present invention to provide an MPEGportable sound reproducing system and a reproducing method thereof whichreproduces sound data, compressed and stored on a memory chip using theMPEG method, into an audible format.

It is another object of the present invention to provide an MPEGportable sound reproducing system which, by storing data on asemiconductor storage medium, prevents heat from generating duringrecording as in the prior art cassette tape player, and avoids damagefrom exposure to heat as with conventional cassette tapes, compactdiscs, and other storage media.

It is still yet another object of the present invention to provide anMPEG portable sound reproducing system which enables connection totelecommunications networks and data vending machines such that variousdata can be downloaded, thereby enabling users to enjoy the benefits-speed, convenience, variety, etc.- of these systems.

It is still yet another object of the present invention to provide anMPEG portable sound reproducing system in which data downloaded viatelecommunications networks and data vending machines as in the above isable to be accessed by and saved on a personal computer.

It is still yet another object of the present invention to provide anMPEG portable sound reproducing system which does not require separatestorage media as with cassette players and compact disc players suchthat the device can be made to be lightweight and thin, and the need forphysical storage space of the storage media is not needed.

To achieve the above objects, the present invention provides an MPEGportable sound reproducing system and a method for reproducing sounddata compressed using the MPEG method. The inventive system includespower supply means for supplying operational power to the system, thepower supply means being realized through a secondary battery; powerprocessing means for rectifying power supplied from the power supplymeans to stable voltage and current; information display means fordisplaying numbers and combinations of letters related to operationalstates of the system; control means for controlling all operations ofconverting and reproducing sound data compressed using the MPEG method;data storage means for storing MPEG-compressed sound data in adesignated address according to signals output from the control means;information selecting means for selecting general operations toreproduce, download, and apply selected sound data stored in the datastorage means; sound reproducing means for converting sound data storedin the data storage means into a format audible to users according tosignals output from the control means; and transmitting/receiving meansfor transmitting and receiving sound data and program data from externaldevices.

The inventive sound reproducing method includes the steps ofinitializing the system and detecting a state of a flash ROM when poweris supplied to information selecting means; loading a main program fromthe flash ROM, if it is detected that the state of the flash ROM isnormal, and completing booting of required software; and downloading andreproducing stored sound data, if the set up of the operationalenvironment is completed, according to signals output from theinformation selecting means, a state of operational power, and whetherconnection is made to an external power supply and to externaltelecommunications systems, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate an embodiment of the invention,and, together with the description, serve to explain the principles ofthe invention:

FIG. 1 is a block diagram of an MPEG portable sound reproducing systemaccording to a preferred embodiment of the present invention;

FIG. 2 is a detailed block diagram of the MPEG portable soundreproductin system of FIG. 1; and

FIGS. 3a-3 f are flow charts of a reproducing method for an MPEGportable sound reproducing system according to a preferred embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail with reference to the accompanying drawings.

Referring first to FIG. 1, an inventive MPEG portable sound reproducingsystem comprises a power supply portion 100, a power processor 200, aninformation selector 300, an information display portion 400, a controlportion 500, a data storage portion 600, a sound reproducing portion700, and a transmitter/receiver 800.

The power supply portion 100 is realized through a nickel-cadmium(Ni—CD), nickel-metal hydride (Ni—MH), lithium-ion, or lithium-polymersecondary battery, and converts chemical energy into electrical energyfor supply of the same to the portable sound reproducing system. Also,the power supply portion 100 is recharged by electricity receivedthrough an adaptor.

The power processor 200 receives power from the power supply portion 100or directly through the adaptor, rectifies the power to stable voltagecurrent, and supplies the power to the control portion 500 as drivepower. When receiving power through the adaptor, the power processor 200supplies power to the power supply portion 100 for recharging the same.

The information selector 300 is realized through various predeterminedkeys operated by the user, and outputs electrical signals according tothe user selections to control the supply of power, extract data forreproduction, control various functions related to the reproduction ofdata, and transmit and receive data.

In more detail, the information selector 300 comprises a forward switchfor advancing to a subsequent selection when pressed for under apredetermined amount of time of preferably under one second, and whichquickly plays data when continually pressed for a predetermined amountof time of preferably over one second; a reverse switch for returning toa beginning of a present selection if the selection is in mid-play orreversing to a previous selection if between selections when pressed forunder a predetermined amount of time of preferably under one second, andwhich quickly plays data in reverse when continually pressed for apredetermined amount of time of preferably over one second; a play/stopswitch for reoproducing data when pressed one time, and, in a state ofreproducing data, discontinuing the present play mode when pressedagain, then cutting off the power; a repeat switch for replaying thepresent selection when pressed one time, repeating all selections whenpressed two times, and cancelling all repeat commands when pressed for apredetermined time of preferably over three seconds; and a random switchfor randomly reproducing the selections in a random order when pressed.

The information display portion 400 is realized through an LCD (liquidcrystal display) and displays various numbers and letters related to thevarious modes realized through the above switches.

The control portion 500 controls all the various operations for storingand reproducing sound data compressed using the MPEG method. The controlportion 500, as shown in FIG. 2, comprises a CPU (central processingunit) 501 for controlling operations related to converting digital datastored using the MPEG method into an audible format; an interruptercontroller 503 for outputting a control signal to control the CPU 501when an input/output operation is ended or an error occurs in the same;a power controller 505 for outputting control signals to stably supplypower applied from the power processor 200 as operational power of theCPU 501, and cutting off power when an error occurs; a keyboardinterface 507 for interfacing key select signals applied from theinformation selector 300; an LCD controller 509 for controlling electriccurrent supplied to a matrix of the information display portion 400 tocontrol display during operation of the inventive sound reproducingsystem; an extended ROM interface 511 for interfacing a with an extendedROM, added to extend a scope of programs or memory, and a flash memory;a timer 513 for counting time information needed for data downloadingand reproducing the downloaded data, and data interrupting required tooperate the system; a bus bridge access controller 519 outputtingcontrol signals for controlling a bus, the bus transmitting data; acontroller 523 for controlling input/output of data transmitted andreceived; a flash ROM controller 527 for activating the flash ROM 603according to interrupter control signals applied from the CPU 501; a DSP(digital signal processor) interface 529 outputting control signals forcontrolling an input/output of digital sound data compressed by the MPEGmethod; and a clock drive 531 which processes a generator clock of agenerator 1000 to a predetermined state and drives the same to the CPU501 as clock signals.

All the above elements of the control portion 500 are connected througha combination of an interrupt line and an I/O bus.

The data storage portion 600 stores sound data compressed using the MPEGmethod downloaded through the transmitter/receiver 800 according tosignals from the control portion 500. Further, as shown in FIG. 2, thedata storage portion 600 is realized through the flash ROM 603, which isa volatile memory element that does not lose data when the power is cutoff, for storing and erasing sound data, and data related to applicationsoftware and other digital data.

The sound reproducing portion 700 converts sound data stored in the datastorage portion 600 into an audible format according to signals appliedfrom the control portion 500. The sound reproducing portion 700, asshown in FIG. 2, comprises a DSP portion 701 for returning digital sounddata compressed using the MPEG method to its initial state, an audioportion 703 which converts sound signals input from the DSP portion 701into an audible format, and headphones/speakers 705 for convertingelectric sound signals input from the audio portion 703 into sound ableto be heard by users.

The transmitter/receiver 800 is connected to a PC, data vending machine,or other such external devices and either transmits sound or programdata thereto or receives sound or program data therefrom. A preferredreproducing method of data compressed using the MPEG method for theportable sound reproducing system structured as in the above will bedescribed hereinafter with reference to FIGS. 3a-3 f.

First, if the user presses an ON switch of the information selector 300to reproduce and listen to particular sound data among all the digitaldata compressed using the MPEG method and stored in the data storageportion 600, the CPU 501 of the control portion 500 enters anoperational mode by receiving power via the power processor 200 from thepower supply portion 100 or adaptor (S1000).

Next, the CPU 501 runs the main program and completes booting ofrequired software (S1300), then determines if key signals of theinformation selector 300, input through the keyboard interface 507 andthe MEM/IO bus, are detected (S1400).

If key signals are detected in step S1400, it is determined if there isa power OFF selection signal, selected by the user to cut off powersupplied from the power processor 200 (S1410). If the power OFF signalis detected, operational power applied from the power processor 200 iscut off and the system is put in a standby mode (S1415).

If no power OFF signal is detected in step S1400, it is detected ifthere has been an input of a sound reproduction signal for restoring andreproducing a selection of data compressed using the MPEG method andstored in the flash ROM 603 of the data storage portion 600 (S1420).

If it is determined in step 1420 that the key signal is a reproductionkey signal to reproduce sound data stored in the data storage portion600, the CPU 501 loads the selected sound data to the DSP portion 701 ofthe sound reproducing portion 700 via the DSP interface 529 of thecontrol portion 500, then returns the digital sound data compressedusing the MPEG method to its original state using operating systemssoftware, converts the data into an electric sound signal through theaudio portion 703 of the sound reproducing portion 700, and converts theelectric signal into a sound signal audible to the user and outputs thesame through headphones/speakers 705 (S1425).

In step 1420, if it is detected that the key select signal is not asignal for reproducing sound data or if the system is currentlyreproducing data, it is then detected if a forward signal has been input(S1430). If a forward key signal is detected in step S1430, the CPU 501determines if the forward select signal; is transmitted for under apredetermined amount of time of less than one second, which if thiscriterion is met, then advances the selection to the next selection andexecutes a reproducing operation, and also determines if the forwardselect signal is transmitted for over a predetermined amount of time ofmore than one second, and if it is, the present selection is reproducedat a fast speed (S1435).

In step S1430, if a forward key signal is not detected, it is determinedif a reverse key signal has been input (S1440). If it has, the currentselection being reproduced is either returned to the beginning, or ifbetween selections, a selection is made to the preceding song if thereverse signal is transmitted for under a predetermined time ofpreferably under one second, or the present playing selection is quicklyreversed if the. reverse signal is transmitted for over a predeterminedamount of time of preferably over one second (S1445).

If a reverse signal is not detected in step 1440, it is then detected ifa stop signal has been input (S1450). Here, if a stop signal isdetected, it is further determined, using an installed program, if asignal of a predetermined number of times of preferably one time hasbeen input and the present mode is the play mode, in which case thepresent reproduction operation is discontinued, an if in a stopped modereproduction is started. Further, in a state where the play mode hasbeen disontinued, if it is detected that the stop signal is transmittedfor a predetermined amount of time of preferably more than threeseconds, standby power is controlled to OFF (S1455).

In step S1450, if a stop signal is not detected or if it is determinedthat the system is in a play mode, it is then determined if a repeatsignal has been input (S1460). If a repeat signal is detected, thenumber of input times is determined using an installed program such thatthe present selection is repeated when it is detected that the signalhas been input a predetermined number of times of preferably one time,all sound data stored in the memory of the flash ROM 603 is repeatedwhen the input of two signals is detected, and any repeat command iscancelled when it is detected that the signal is input during a repeatoperation (S1465).

Further, if no repeat signal is detected in, step 1460, it is thendetermined if a random signal has been input (S1470). If a random signalis detected in this step, selections are reproduced in random order(S1475), and if a random signal is not detected, the operation toreproduce the sound data compressed using the MPEG method is repeated.

In the above state where sound data selected by the user is beingreproduced according to key signals input from the information selector300, operational power is analyzed in the power processor 200 todetermine if a Low Power state exists, disenabling a reproductionoperation to be performed, in the power supply portion 100 (S1500). Ifit is determined that the power supply portion 100 is in a Low Powerstate in step 1500, it is then determined if the detected presentvoltage is below a predetermined standard value that would impede thenormal reproducing of sound data (S1510).

In the above, if it is determined that the voltage of the power supplyportion 100 is less than the predetermined standard value, the controlportion 500 outputs a predetermined control signal for display of awarning to the LCD controller 509 via the MEM/IO bus. Here, the LCDcontroller 509 adjusts power supplied to the matrix of the informationdisplay portion 400 such that a “power cut off” message is displayedthereon (S1520).

Simultaneously with the displaying of the “power cut off” message, theCPU 501 of the control portion 500 inputs a data storage signal to theflash ROM 603 of the data storage portion 600 such that the presentstate is saved (S1530), and controls the power controller 505 via theMEM/IO bus to cut off the supply of power to the power processor(S1540).

In step 1510, if it is determined that the voltage of the power supplyportion 100 is above the predetermined standard value, enabling thenormal operation of the system, the control portion 500 controls theinformation display portion 400 via the LCD controller 509 such that a“Low Power” message is displayed (S1550).

After the checking of the power state in step S1500, the CPU 501 of thecontrol portion 500 determines if the power processor 200 is connectedto an external power source through the adaptor (S1600). If it isdetected that there is a connection with an external power source instep S1600, it is then determined if the power supply portion 100 isfully charged (S1610).

In the above, if it is determined that the power supply portion 100 isfully charged, the charging operation is discontinued, to prevent damageto the power supply portion 100 caused by overcharging, and if it isdetermined that the power supply portion 100 is not fully charged, it isthen determined if power from an external power source is being suppliedthrough the adaptor (S1620). Here, if external power is being suppliedin a state where the power supply portion 100 is not fully charged, thepower is then supplied to the power supply portion 100 to charge thesame (S1630).

After step 1600, where it is determined if there is a connection with anexternal power source, it is then determined if sound data is beingreproduced according to selections made by the user at the informationselector 300 (S1700). If sound data is being reproduced in this step,the CPU 501 of the control portion 500 analyzes the sound data-checking, for example, data reproduction time, title of selection, typeof music, remaining play time for the selection, etc.- and displays theinformation through the information display portion 400 by controllingthe LCD controller 509 (S1710).

Further, the CPU 501 of the control portion 500 accesses the sound datacompressed using the MPEG method in the flash ROM 603 of the datastorage portion 600, and transmits this sound data to the DSP portion701 of the sound reproducing portion 700 through the DSP interface 529.Accordingly, the DSP portion 701 processes the MPEG-compressed digitalsound data to a predetermined state and converts it to sound signals viathe audio portion 703, then reproduces the sound data throughheadphones/speakers 705 such that the user can listen to the sound(S1720).

Next, it is determined if the selected sound data has been completelyreproduced (S1730). If it has, a subsequent sound data selection issearched from the flash ROM 603 (S1740), then sound data to bereproduced is loaded from the flash ROM 603 and preparations are made toreproduce sound data (S1750).

After step S1700, where it is determined if sound data is beingreproduced, the CPU 501 of the control portion 500 analyzes signals fromthe controller 523 to determine if the transmitter/receiver 800 isconnected to an external telecommunications system of, for example, acomputer having a modem or other telecommunications device installedtherein, or a data vending machine selling a variety of data andprograms of music, video games, etc. (S1800).

If it is determined in step 1800 that the transmitter/receiver 800 isconnected to an external telecommunications system, the inventive systemis changed to a downloading load, the data is downloaded (S1810), and itis determined if an error exists in the downloaded data (S1820).

In the above, if it is determined that an error exists in the downloadeddata, the CPU 501 of the control portion 500 performs control so thatthe data is re-transmitted, and if no error exists in the data, the datais stored (S1830). Further, if it is determined that no error exists inthe transmitted data in step 1820, the CPU 501 determines iftransmission of the data is completed (S1840), designates an addresssphere in the data storage portion 600, then downloads and stores thedata (S1850).

In the MPEG portable sound reproducing system structured and reproducingMPEG-compressed data as in the above, as sound data is compressed usingthe MPEG method and stored in a semiconductor chip or other memoryelement, then reproduced in a format audible to the user, convenience isprovided by eliminating the need for records, tapes, CDs, and other suchmemory media, and many of the drawbacks of using memory media in priorart reproduction devices- reduction in sound quality after recording orrepeated playing, fragility of memory media necessitating the need totake great care in storing the same, etc.- are overcome.

Further, because it is possible to connect the inventive system totelecommunications networks and data vending machines to downloadvarious data, benefits of speed, convenience, and low cost are providedto the user.

Other embodiments of the invention will be apparent to the skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with the true scope and spiritof the invention being indicated by the following claims.

What is claimed is:
 1. A portable sound reproducing system for reproducing compressed digital sound data into an audible audio signal, comprising: a Direct Memory Access (DMA) Bus across which a received compressed digital sound data is stored and across which the stored sound data is accessed to be reproduced; a MEM/IO Bus across which a control data signal is provided to control operations on said DMA Bus; a Bus Bridge Access Controller interposed between said DMA Bus and said MEM/IO Bus that selectively controls operations on said DMA Bus to selectively store the received compressed digital sound data and to selectively resume an operation to reproduce the stored sound data in accordance with the control signal from said MEM/IO Bus; a CPU connected to said MEM/IO Bus that controls operations related to conversion of the stored sound data into an audible format; an interrupter controller connected to said MEM/IO Bus that outputs a further control signal to control the CPU when an input/output operation is ended or an error occurs in the CPU; a power controller connected to said MEM/IO Bus to stably supply power from a power processor as operational power to the CPU, and for cutting off the power when an error occurs; a keyboard interface connected to said MEM/IO Bus that interfaces key select signals applied from an information selecting means; an LCD controller connected to said MEM/IO Bus that controls electric current supplied to a matrix of an information display means to control a display during operation of the sound reproducing system; an extended ROM interface connected to said MEM/IO Bus that interfaces a connection with an extended ROM that can be added to extend a scope of programs or memory; and a timer connected to said MEM/IO Bus that counts time information needed for receiving a data download and for reproducing the downloaded data, and data interrupting required to operate the system.
 2. The sound reproducing system of claim 1, further comprising: a transmitter/receiver whereby the system is adapted to be connected to an external source of the compressed digital sound data; a controller connected between said transmitter/receiver and said DMA Bus that controls input/output of transmitted and received compressed digital data; a flash ROM controller connected to said DMA Bus that activates a flash ROM according to interrupter control signals applied from a CPU; and a DSP interface connected to said DMA Bus that outputs control signals that control the input/output of compressed digital sound data that has been compressed by a data compression method.
 3. The sound reproducing system of claim 2 wherein said data compression method is an MPEG compression method.
 4. The sound reproducing system of claim 2, further comprising: a DSP portion connected to said DSP interface that processes the compressed digital sound data to a predetermined state; and an audio portion connected to said DSP portion which converts audio signals input from the DSP portion into an audible format.
 5. The sound reproducing system of claim 1, further comprising: a RAM, which is a volatile memory element that loses data when power is cut off, for loading application software and temporarily storing the same while a reproducing operation is being executed after power is supplied to the system; and a flash ROM, which is a volatile memory element that does not lose data when the power is cut off, for storing and erasing sound data, and data related to application software and other digital data.
 6. The sound reproducing system of claim 1, further comprising: a power supply that supplies operational power to the system, the power supply being realized through a secondary battery; a power processor that rectifies power supplied from the power supply to stabilize voltage and current; an information display that displays numbers and combinations of letters related to operational states of the system; control means for controlling all operations of converting and reproducing the compressed sound data; data storage means for storing the compressed sound data in a designated address according to signals output from the control means; an information selector for selecting general operations to reproduce, download, and apply a selected sound data stored in the data storage means; a sound reproducing means for converting the selected sound data into a format audible to users according to signals output from the control means; and a transmitting/receiving means for transmitting and receiving compressed digital sound data and program data to and from external devices.
 7. The sound reproducing system of claim 6, wherein the power processor supplies charging current to the secondary battery of the power supply when the power processor receives external power through an adapter.
 8. The sound reproducing system of claim 6, wherein the information selector comprises: a forward switch for advancing to a subsequent selection when pressed for under second, and which quickly plays a present selection when continually pressed for over one second; a reverse switch for returning to a beginning of the present selection if the selection is in mid-play or reversing to the previous selection if between selections when pressed for under one second, and which quickly plays data in reverse when continually pressed for a predetermined amount of time of over one second; a play/stop switch reproducing data when pressed one time, and in a play mode, discontinuing a play mode when pressed then cutting off the power; a repeat switch for replaying the present selection when pressed one time, repeating all selections when pressed two times, and canceling all repeat commands when continually pressed; and a random switch for randomly reproducing the selections in a random order when pressed.
 9. A portable sound reproducing system for reproducing compressed digital sound data into an audible audio signal, comprising: a Direct Memory Access (DMA) Bus across which a received compressed digital sound data is stored and across which the stored sound data is accessed to be reproduced; a MEM/IO Bus across which a control data signal is provided to control operations on said DMA Bus; a Bus Bridge Access Controller interposed between said DMA Bus and said MEM/IO Bus that selectively controls operations on said DMA Bus to selectively store the received input sound data and to selectively resume an operation to reproduce the stored sound data in accordance with the control signal from said MEM/IO Bus; a transmitter/receiver whereby the system is adapted to be connected to an external source of the compressed digital sound data; a controller connected between said transmitter/receiver and said DMA Bus that controls input/output of transmitted and received digital sound data; a DSP interface connected to said DMA Bus that outputs control signals that control the input/output of compressed digital sound data that has been compressed by a data compression method; a CPU connected to said MEM/IO Bus that controls operations related to conversion of the stored sound data into an audible format; a flash ROM controller connected to said DMA Bus that activates a flash ROM according to interrupter control signals applied from the CPU; an interrupter controller connected to said MEM/IO Bus that outputs a further control signal to control the CPU when an input/output operation is ended or an error occurs in the CPU; a power controller connected to said MEM/IO Bus to stably supply power from a power processor as operational power to the CPU, and for cutting off the power when an error occurs; a keyboard interface connected to said MEM/IO Bus that interfaces key select signals applied from an information selecting means; an LCD controller connected to said MEM/IO Bus that controls electric current supplied to a matrix of an information display means to control a display during operation of the sound reproducing system; an extended ROM interface connected to said MEM/IO Bus that interfaces a connection with an extended ROM that can be added to extend a scope of programs or memory; and a timer connected to said MEM/IO Bus that counts time information needed for receiving a data download and for reproducing the downloaded data, and data interrupting required to operate the system. 